Automated selective wash method and apparatus

ABSTRACT

An automated and selective wash method and apparatus for separating desired material from atmospheric particles after deposition on an adhesive coated surface.

United States Patent 191 Brumbaugh AUTOMATED SELECTIVE WASH METHOD AND APPARATUS [75] Inventor: Allen D. Brumbaugh, Frederick Md.

[73] Assignee: The United States of America as represented by the Secretary of the Army, Washington, DC.

[22] Filed: Apr. 26, 1972 [21] Appl. No.: 247,658

521 115.0. 73/28 511 int. Cl. G0ln31/00 [58] Field of Search 73/28, 61 R, 53,

[56] References Cited UNITED STATES PATENTS 2,076,554 Drinken, 73/28 [451 Sept. 25, 1973 2,312,295 2/1943 Dahlman 73/28 2,947,382 8/1960 Orr 73/28 3,523,733 73/432 PS 8/1970 Kling Primary Examiner-S. Clement Swisher Attorney-Harry M. Saragovitz et a1.

[ ABSTRACT An automated and selective wash method and apparatus for separating desired material from atmospheric particles after deposition on an adhesive coated surface.

7 Claims, 1 Drawing Figure AUTOMATED SELECTIVE WASH METHOD AND APPARATUS DEDICATORY CLAUSE known, such as disclosed in US; Pat. No. 3475965, all

of the prior art means presented one or more problems which include permitting undesired particles entering the detection means, no means provided for selective detection of predetermined particles, no provision to utilize a variety of wash liquids, no provision to utilize a small volume of wash liquid to result in a highly concentrated detection sample, and loss of signal due to background noise craated by the presence of undesirable particles in the detection means. My invention was conceived and reduced to practice to solve the aforementioned problems and to satisfy the long felt need for an automated and selective wash method and apparatus for separating desired material from the atmosphere.

My invention has utility for medical and environmental atmospheric monitoring.

A principal object of my invention is to provide an apparatus and method to increase the ability of the art to determine the presence of selected airborne materials in ambient air by transferring them to a liquid and retaining the undesired particles on an adhesive coated surface.

Another object of my invention is to provide an apparatus and method for continuously separating selected material which has beenmixed with undesirable aerosol material.

A further object of my invention is to provide an apparatus and method that will prevent undesirable particulate material from entering a system. I

A further object of my invention is to provide an apparatus and method wherein various kinds and combinations of wash liquid may be used to accomplish separation to enhance identification of the material that is separated.

A still further object of my invention is to provide an apparatus and method wherein the particles not removed can be used to furnish reference information by optical scan or microscopic observation and particles can be tagged or stained without removal of any material. 1

Other objects of my invention will be obvious or will appear from the specification hereinafter set forth.

The drawing is a schematic view of my apparatus.

My invention, as shown in the drawing, will now be described in detail as follows.

The point of novelty of my selective wash method and apparatus can be understood by describing its pres,- ent application which is the separation of microbiological material and accompanying carrier medium of man-made aerosol particles from the ambient background particles in air samples. The mixture of particles from the sample is deposited by means of an impactor onto adhesive coated tape 1, driven in the conventional manner between feed reel 2 and take up reel surface in the wash head is 6 mm wide, 19 mm long, has

3, any microbiological aerosol particles dissociate to release microbial cells and carrier medium while the background particles remain attached to the adhesive because of their uniparticulate nature; the adhesive being any suitable adhesive coating for a given application which is not soluble in the particular wash liquid utilized. Therefore, essentially no background particles get into the wash liquid unless coincidently impacted on a deposited aerosol particle.

To operate my apparatus, as shown in the drawi'ng, an air sample is drawn into concentrator 5 and the concentrated sample passed to impactor 4 in the conventional manner to impact particles on adhesive tape 1. Adhesive is applied to the tape in the conventional manner by conventional adhesiveapplicator 6 and heater means 7. Desired particles are removed from the adhesive tape by a predetermined wash liquid being pumped by conventional pump'9 from reservoir 8 and circulated through wash head 11 where contact is made with the deposited particles to transfer the desired material to the wash liquid.

The effluent from the wash head containing the desired material is transferred by conventional pump 9 to tank 10 as shown in the drawing or to a conventional sensing or detection device. Particles remaining on the tape can also be analyzed by conventional detection means as desired.

The tape drive and impactor subcombinations of my invention are conventional; the solid surface used for impaction is conventional 16 mm plastic film leader tape; the adhesive is diluted with xylene to a 10 percent to 25 percent solution and applied to the tape from a meniscus; the air sample collector is a 1,000 liter per minute aerosol concentrator having an output which is impacted at 5 liters per minute onto the tape in a trace about 5 mm wide; the tape moves at a selected rate of from 2 to 4 inches per minute; and the liquid contact a volume of 0.1 cc, and has a flow-through time of 20 seconds. The pumping rate for the input volume of the wash liquid to the wash head is equal to or less than that for the effluent volume to insure no loss of sample.

It is obvious that other modifications can be made of my invention, and I desire to be limited only by the scope of the appended claims.

I claim:

1. An apparatus for medical and environmental monitoring of atmospheric content by selective separation of material from the particles of interest from admixtures with ambient particles in air samples, the apparatus comprising a continuously moving impaction surface, a concentrator means and an impactor means wherein the improvement in combination therewith comprises an adhesive coating on said moving impaction surface for deposition of particles in combination with a means to apply the adhesive coating and a wash system consisting of a wash head thru which the impaction surface moves in combination with a wash liquid to contact-wash the impacted particles and transfer desired material to the wash liquid.

2. The apparatus of claim 1 wherein the adhesive coating consists of 10 percent to'25 percent solution to adhesive in xylene.

3. The apparatus of claim 1 wherein the means to apply the adhesive coating comprises of an applicator for the diluted adhesive, a healer for evaporating the diluting solvent to insure adherence of particles.

to an impactor, impacting the air sample onto a surface with an adhesive coating thereon, adhering particles within the air sample to the adhesive coating, transferring desired material from the adhering particles to a wash liquid, and monitoring the transferred desired material by a detection means. 1

7. The method of claim 5 wherein the adhering particles are microbiological cells to be dissociated. 

1. An apparatus for medical and environmental monitoring of atmospheric content by selective separation of material from the particles of interest from admixtures with ambient particles in air samples, the apparatus comprising a continuously moving impaction surface, a concentrator means and an impactor means wherein the improvement in combination therewith comprises an adhesive coating on said moving impaction surface for deposition of particles in combination with a means to apply the adhesive coating and a wash system consisting of a wash head thru which the impaction surface moves in combination with a wash liquid to contact-wash the impacted particles and transfer desired material to the wash liquid.
 2. The apparatus of claim 1 wherein the adhesive coating consists of 10 percent to 25 percent solution to adhesive in xylene.
 3. The apparatus of claim 1 wherein the means to apply the adhesive coating comprises of an applicator for the diluted adhesive, a healer for evaporating the diluting solvent to insure adherence of particles.
 4. The apparatus of claim 1 wherein the adhesive coating is insoluble in the wash liquid.
 5. The apparatus of claim 1 wherein the pumptng rate for the input volume of wash liquid to the wash head is equal to or less than that for the effluent volume to insure no loss of sample.
 6. A method for medical and environmental monitoring of atmospheric content by selective separation of desired material comprising the steps of concentrating an air sample, circulating the concentrated air sample to an impactor, impacting the air sample onto a surface with an adhesive coating thereon, adhering particles within the air sample to the adhesive coating, transferring desired material from the adhering particles to a wash liquid, and monitoring the transfErred desired material by a detection means.
 7. The method of claim 5 wherein the adhering particles are microbiological cells to be dissociated. 